A drainage trench or channel of polyester concrete is known, for example, from European Patent No. 112,187. This channel has proved to be very reliable, particularly for applications such as roads, airports or airfields. However, facilities housing food processing operations such as, for example, dairies or meat plants are typically moist, and it is therefore preferable for hygienic reasons to form the channel from a substantially non-porous material such as chrome steel or other stainless steel, instead of polyester concrete.